1. Field
This disclosure relates to any service any port (ASAP), more particularly to managing call routing in accordance with policy on ASAP systems.
2. Background
Network wholesalers may manage their various policies on their network in a policy system. The policies may include port policies, such as the number of active ports allowed for a particular point-of-presence (POP), the number of active users associated with a particular customer allowed under a service level agreement with that customer, as well as the levels of service provided for a particular customer.
For example, a wholesaler may have an agreement with an Internet Service Provider (ISP) that guarantees a certain quality of service for that ISP for 10,000 active calls on a particular set of POPs for the wholesalers network, with a best effort overage of 3,000 calls. The policy system would maintain the current state of the network and would determine how many calls are associated with that ISP and would accept or reject calls from users associated with the ISP based upon the state of the network. Included in the ‘dial’ calls may be Voice over Internet Protocol (VoIP) calls.
VoIP calls impact the various policies and the pool of resources that could also be used for dial calls. Typically, universal gateways, which provide entrance to the network, are provisioned to issue pre-authentication messages prior to accepting a call, allowing policy decisions to impact which calls are accepted. However, most VoIP networks are provisioned to adjust call routing based upon available hardware resources, not on ASAP policies. An originating network may have several choices to route the call to various terminating networks, and may do so using least-cost call routing, without any policy influences.
This mismatch between routing decisions and acceptance decisions may lead to an endless loop. As such, terminating networks may prematurely accept an originating network's call accept request, then later reject that call accept request after a gateway resource was committed to accept another call in the meantime. This is known as ‘glare’ and can lead to circular routing decisions.
For example, the originating network routes the call to the terminating network as it sees the terminating network as the least-cost option. Today's networks may not link policy control to terminating network call control. The terminating network has a policy constraint that causes it to reject the call. The originating network, not basing decisions on policy, continues to route the call to that terminating gateway, which continues to reject the call.